Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids. It is based on a hierarchical design targeted at federations of clusters. Supports clusters up to 2000 nodes in size.

GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. Designed for interoperability, it publishes data from any major spatial data source using open standards: WMS, WFS, WCS, WPS and REST

JasperReports Library, the world's most popular open source business intelligence and reporting engine and JasperReports Server, the most popular open source interactive report server built-on JasperReports Library

iText is a PDF library that allows you to CREATE, ADAPT, INSPECT and MAINTAIN documents in the Portable Document Format (PDF):
- Generate documents and reports based on data from an XML file or a database
- Create maps and books, exploiting numerous interactive features available in PDF
- Add bookmarks, page numbers, watermarks, and other features to existing PDF documents
- Split or concatenate pages from existing PDF files
- Fill out interactive forms
- Serve dynamically generated or manipulated PDF documents to a web browser
iText is used by Java, .NET, Android and GAE developers to enhance their applications with PDF functionality.
iTextSharp is the .NET port.
Several iText engineers are actively supporting the project on the iText mailing-list itext-questions@lists.sourceforge.net and on StackOverflow: http://stackoverflow.com/questions/tagged/itext